This would be a nice feature although I'm not sure how it would work. Even multiple samples per instrument have to be assigned to individual notes. I would have to do it by tracking out the whole sequence, duplicating the column and then assign another instrument to the new column.

That is the sort of thing I have been doing.
Thinking about it now, I could just render a doubled up sample.
I had been duplicating columns before. Including effects etc.
It is handy to have doubled octave leads. Or detuned synth lines

Isn't mixing sound what we used to do in tracking? I'm sure I did. I remember having a bdrum sample, bdrum/cym, cym/snare, cym, bdrum/cym/snare mix. To get a decent manual drum beat on a single track in octamed. Or a bdrum, bdrum/bass, etc so I could have a bass/drum on a single track. 'sigh'. Them were the days.